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A104360
Number of distinct prime factors of A104357(n) = A104350(n) - 1.
8
0, 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 2, 2, 2, 1, 2, 3, 3, 1, 3, 3, 3, 1, 2, 4, 4, 2, 2, 5, 4, 2, 3, 2, 3, 1, 3, 4, 3, 5, 3, 4, 4, 5, 1, 3, 4, 2, 2, 2, 3, 1, 2, 3, 2, 3, 1, 4, 1, 3, 4, 6, 4, 4, 2, 6, 1, 5, 4, 4, 1, 2, 5, 7, 4, 5, 3, 4, 4, 5, 4, 5, 2, 4, 4, 5, 3, 3, 3, 2, 5, 2, 5, 4, 7, 2, 5, 3, 2, 6, 3, 4, 2, 3, 3, 3, 5, 4, 3, 5, 2
OFFSET
2,7
FORMULA
a(n) = A001221(A104357(n)).
MATHEMATICA
A104350[n_] := Product[FactorInteger[k][[-1, 1]], {k, 1, n}]; PrimeNu[Table[A104350[n] - 1, {n, 2, 50}]] (* G. C. Greubel, May 10 2017 *)
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Mar 06 2005
EXTENSIONS
a(51)-a(74) from Amiram Eldar, Feb 12 2020
More terms from Jinyuan Wang, Apr 02 2020
Terms a(90) onward from Max Alekseyev, Oct 03 2022
STATUS
approved